CodeForces B. Karen and Coffee

#include<iostream>#include<math.h>  #include<stdlib.h>#include<string.h> int num[200005];using namespace std;int main(){    int n, k, q;    while (cin>>n>>k>>q)    {               int l, r;        memset(num, 0, sizeof(num));        for (int i = 0; i<n; i++)               {            cin >> l >> r;            num[l]++;            num[r + 1]--;        }        memset(c, 0, sizeof(c));        for (int i = 1; i <= 200000; i++)        {            num[i] += num[i - 1];            c[i] += c[i - 1] + (num[i] >= k);        }        for (int i = 0; i<q; i++)        {            cin >> r >> l;            cout << c[l] - c[r - 1] << endl;        }    }    return 0;}